Nicotine, a major alkaloid, is present in tobacco products as well as in smaller amounts in potatoes, tomatoes, and eggplants. Although it is the addictive compound in cigarettes, nicotine is believed to play a protective role in neurodegenerative disorders such as Parkinson's disease. Researchers have found that the short-term administration of nicotine may help improve the memory process by reducing oxidative stress in the brain. Our studies have shown that, by blocking Fenton's reaction, nicotine is able to inhibit free radical generation, so this research has focused on the antioxidant properties of nicotine. The cell lines of the alveoli, blood brain barrier, liver, and Chinese hamster ovaries were treated with 1mM of nicotine for 2 hours, and then the reactive oxygen species were measured. Results showed that the decrease in reactive oxygen species might be due to the inhibition of Fenton's reaction by metal chelation. The metal chelating property of nicotine was tested and its chelating ability was confirmed. Moreover, a study was made of the effects of nicotine on glutathione levels in alveolar cells that were treated with 0.4mM tert-butyl hydroperoxide for 3 hours. Results showed that nicotine prevented the depletion of glutathione levels in the tertiary butyl hydro peroxide treated group. These findings indicate that nicotine in both conventional and electronic cigarettes may alleviate symptoms of some neurodegenerative disorders by reducing oxidative stress caused by free radicals. However, the smoke from the burning tobacco in conventional cigarettes contains many harmful carcinogenic compounds in addition to nicotine. This is not the case with e-cigarettes, which also contain nicotine, but do not have the accompanying toxic materials.